The world's largest science machine, the Large Hadron Collider (LHC), is facing a pivotal moment after its groundbreaking discovery of the Higgs boson. As it prepares for its third 'Long Shutdown', the question arises: what's next for this colossal experiment? The LHC, nestled beneath the Franco-Swiss border, has been a beacon of scientific exploration since its first collisions in 2009. Its primary mission has been to uncover the mysteries of the universe by smashing protons together at nearly the speed of light, analyzing the resulting debris for clues about the fundamental building blocks of matter. The LHC's most notable achievement was the discovery of the Higgs boson in 2012, a particle that gives mass to other elementary particles. This discovery confirmed a theory that had been proposed decades earlier, earning Peter Higgs and François Englert the Nobel Prize in Physics in the following year.
However, the LHC's success in verifying the Standard Model of particle physics has also revealed its limitations. While it has confirmed the existence of quarks, the elementary particles that form protons and neutrons, and has even discovered exotic hadrons like tetraquarks and pentaquarks, it has yet to provide evidence of dark matter or dark energy, which together make up 95% of the universe. The LHC's upgrade, known as the 'High Luminosity' LHC, aims to increase the rate of collisions and the number of net collisions, potentially leading to the discovery of exotic particles and a deeper understanding of the universe's origins. This upgrade is a significant undertaking, costing roughly $1.5 billion and taking four years to complete.
Looking beyond the LHC, CERN is considering the Future Circular Collider (FCC), a proposed electron-positron collider that would be even more powerful than the LHC. The FCC aims to explore the mysteries of dark matter and energy, as well as test the theory of supersymmetry, which suggests that every known particle has a heavier, undiscovered partner. However, the FCC's first phase is met with skepticism by some physicists, who argue that it would primarily provide more precise measurements of known quantities rather than groundbreaking discoveries. The decision to build the FCC is due around 2028, with an estimated cost of nearly $19 billion.
The LHC's journey and the potential future of the FCC raise important questions about the direction of particle physics research. As CERN physicist Archana Sharma notes, the process of decision-making and collaboration at CERN is a complex and inclusive one, with a focus on the desire to contribute rather than geographic location. The LHC's success in verifying the Standard Model has been a testament to the power of international collaboration and the pursuit of scientific knowledge. As the LHC and its potential successors continue to push the boundaries of our understanding, the scientific community must remain vigilant in its quest for knowledge, ensuring that the pursuit of discovery remains a driving force in the face of challenges and uncertainties.
